1. Technical Field
The present disclosure relates to a light-emitting device and a light-emitting apparatus each having a photoluminescent layer that can emit light in the infrared region.
2. Description of the Related Art
Infrared rays (hereinafter also referred to as “infrared light”) are utilized in various applications. For example, infrared rays are utilized for observation of the interior of the living body, examination of the composition of substances, such as foods and chemicals, biometric authentication, and infrared communication. These applications require precise irradiation of the target with infrared rays in a predetermined wavelength range.
In general, photoluminescent materials that emit electromagnetic waves, such as infrared light and visible light, emit light in all directions. Thus, emission of an electromagnetic wave in a particular direction often requires an optical component, such as a reflector or lens. For example, Japanese Unexamined Patent Application Publication No. 2010-231941 discloses a visible light illumination system with sufficient directionality including a light distributor and an auxiliary reflector.